Flat surface grinding machine with a second wheelhead for machining broaches

ABSTRACT

Grinding machine ( 1 ) comprising a first wheelhead ( 4 ) for machining flat surfaces and a second wheelhead ( 10 ) for machining workpieces ( 3 ) such as broaches. The first wheelhead ( 4 ) is slidably mounted on a vertical column ( 6 ) and has a slide ( 7 ) on its underside. The second wheelhead ( 10 ) is rotatable about its own axis and is slidably mounted on said slide ( 7 ). When the first wheelhead ( 4 ) is in its working position, the second wheelhead ( 10 ) is placed away from the workpiece ( 3 ) on the slide ( 7 ) in its rest position (A), and, when the second wheelhead ( 10 ) is in its working position (B), said second wheelhead ( 10 ) is placed next to the workpiece ( 3 ), angularly oriented in order to carry out the helical machining.

TECHNICAL FIELD

[0001] The present invention relates to grinding machines and morespecifically to flat surface grinding machines and to grinding machinesfor machining workpieces such as broaches.

PRIOR ART

[0002] Grinding machines that have a tangential wheelhead and grind flatsurfaces are well known.

[0003] Specific sharpening machines for manufacturing broaches of anytype are also well known.

[0004] U.S. Pat. No. 3,851,563 discloses a machine for machiningworkpieces such as broaches. The machine has a single wheelhead andenables the wheelhead to be orientated in such a way that the helicalgrinding of the workpiece can be executed at a given angle.

[0005] U.S. Pat. No. 4,461,121 describes a grinding machine with atleast three wheels offering the possibility of the relative positioningof the workpiece to be ground and the wheels so as to execute saidworkpiece in accordance with the specifications that this is to have.

DISCLOSURE OF THE INVENTION

[0006] The object of the invention is to provide a flat surface grindingmachine that has a second wheelhead for machining workpieces such asbroaches, as defined in the claims.

[0007] With the machine that is the object of the invention, aconventional flat surface grinding machine may also be used formachining broaches by including for this purpose a second retractingwheelhead rotatable about its own axis.

[0008] The advantages that stem from the invention are as follows:

[0009] There is no need to build a machine specifically for machiningbroaches, as the flat surface grinding machine may be used.

[0010] A sturdy machine is obtained.

[0011] The working of the machine is simple. The transition frommachining with the first wheelhead to machining with the secondwheelhead and vice versa is done by numeric control by means of thevertical movement of the first wheelhead and the horizontal movement ofthe second wheelhead in relation to the first wheelhead, no other typeof operation, such as the manual replacement of one wheelhead foranother, being necessary.

[0012] When the second wheelhead is in the rest position the arrangementis such that it does not restrict the travel of the machine.

DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is an elevational view of the machine of the invention inthe position in which the second wheelhead is retracted and theworkpiece is being ground with the wheel of the first wheelhead.

[0014]FIG. 2 is an elevational view of the machine of the invention inthe position in which the workpiece is being machined with the wheel ofthe second wheelhead.

DETAILED DISCLOSURE OF THE INVENTION

[0015] With reference to FIG. 1, the grinding machine 1 has a machiningtable 2 on which the workpiece 3 to be machined is secured. The machine1 comprises a first wheelhead 4, with its respective wheel 5, with theoption of vertical movement in relation to a fixed vertical column 6.The workpiece 3 is situated between a headstock and a tailstock. Theheadstock allows the workpiece 3 to rotate in respect of its own axis.

[0016] On its underside the first wheelhead 4 has a slide 7 with ashifting pedestal 8 that moves on said slide 7. Said shifting pedestal 8is linked to an index plate 9, which is linked in turn to a secondwheelhead 10, with its respective wheel 11. In this way, the wheelhead10 can slide longitudinally in relation to the main wheelhead 4 and mayin turn rotate in respect of its own axis.

[0017] In FIG. 1 the wheelhead 10 is in its rest position (position A)and it is the wheel 5 that is grinding. In FIG. 2 said wheelhead 10 isin its working position (position B), while the wheel 11 is being used.To pass from the position of FIG. 1 to the position of FIG. 2, the firstwheelhead 4 moves according to the vertical axis on column 6. Theshifting pedestal 8 then moves on the slide 7 until the wheelhead 10reaches its working position on the workpiece 3. The horizontal movementof the wheelhead 10 and the horizontal movement of the workpiece 3 areperpendicular.

[0018] The index plate 9 enables the wheelhead 10 to turn in respect ofits own axis, whereby the wheel 11 can attack the workpiece 3 at acertain angle set at the numeric control. In this way, the helicalgrinding of the workpiece 3 is carried out by combining the movement ofsaid workpiece 3 in respect of said wheel 11 with the simultaneousrotation of the workpiece 3 in respect of its own axis. The workpiece 3is rotated by way of the headstock to which said workpiece 3 isattached, the speed of the aforesaid rotation being governed by numericcontrol.

1. Grinding machine for machining flat surfaces and workpieces such as broaches, comprising: means for horizontally displacing the workpiece to be machined and means for rotating said workpiece in respect of its own axis, a vertical column, a first wheelhead for machining flat surfaces slidably mounted on said vertical column and substantially vertically movable with respect of said column, said first wheelhead having a slide on its underside, and a second wheelhead for machining workpieces such as broaches rotatable about its own axis, said second wheelhead being slidably mounted on said slide and being substantially horizontally movable with respect of said slide, wherein, when the first wheelhead is in its working position, the second wheelhead is placed away from the workpiece on the slide in its rest position, and, when the second wheelhead is in its working position, said second wheelhead is placed next to the workpiece, angularly oriented in order to carry out the helical machining, the transition from the rest position to the working position of the second wheelhead and vice versa being done by means of the vertical movement of the first wheelhead and the horizontal movement of the second wheelhead.
 2. Grinding machine according to claim 1, wherein the second wheelhead is mounted on the slide by means of an index plate and a shifting pedestal.
 3. Grinding machine according to claim 1, wherein the horizontal movement of the workpiece and the horizontal movement of the second wheelhead are perpendicular. 